Dual clutch transmissions of this type have, besides a good efficiency, the advantage that, among other things, they can be shifted or engaged automatically, in particular, without interruption of the tractive force, wherein, in the respectively non-activated sub-transmission, a gear step can already be preselected and then activated by switching the power-shift clutches. In the process, the odd gears (1, 3, 5, etc.) in one sub-transmission and the even gears (2, 4, 6, etc.) in the other sub-transmission are positioned by means of corresponding gear wheel sets, which are in driving connection with the respective input shaft or the output shaft via, for example, synchronous clutches.
The axial length of the dual clutch transmission depends on the number of gear wheel sets or wheel planes that are arranged in the dual clutch transmission in succession in the axial direction. Each of the wheel planes is made up of at least two fixed gear wheels and/or detached gear wheels. Arranged between the wheel planes are shift elements that, when actuated, enable the engagement of forward and reverse gears.
A dual clutch transmission of the generic type has gear wheel sets that can be engaged via shift elements and, in particular, form exactly eight wheel planes. The wheel planes are each associated with a first sub-transmission and a second sub-transmission. Each of the sub-transmissions has a respective input shaft as well as a common output shaft. The mutually coaxial input shafts can be activated via a particular power-shift clutch in alternation, wherein the even forward gears are associated with the first sub-transmission and the odd forward gears are associated with the second sub-transmission, and, when a shift of gear occurs, these gears can be engaged via the shift element. In the generic dual clutch transmission, at least two wheel planes of a sub-transmission are each formed both by drive-side gear wheels, which are detachably mounted rotatably on the input shaft, and by output-side gear wheels, which are detachably mounted rotatably on the output shaft and mesh with the former gear wheels. The detachably mounted gear wheels of the two wheel planes can be coupled by means of shift elements to the input shaft and/or to the output shaft. In this way, the two wheel planes can be decoupled, that is, idled, in part or in full from the input shaft/output shaft. As a result of this, the moment of inertia of the activated sub-transmission is reduced advantageously.